Introduction: In the context of poverty and HIV and AIDS, peer education is thought to be capable of providing vulnerable youth with psychosocial support as well as information and decision-making skills otherwise limited by scarce social and material resources. As a preventative education intervention method, peer education is a strategy aimed at norms and peer group influences that affect health behaviours and attitudes. However, too few evaluations of peer-led programmes are available, and they frequently fail to reflect real differences between those who have been recipients of peer education and those who have not. This article reports on an evaluation of a pilot peer-led intervention, entitled Vhutshilo, implemented on principles agreed upon through a collaborative effort in South Africa by the Harvard School of Public Health and the Centre for the Support of Peer Education (the Rutanang collaboration). Vhutshilo targeted vulnerable adolescents aged 14 -16 years living in some of South Africa's under-resourced communities. Methodology: The research design was a mixed-method (qualitative and quantitative), longitudinal, quasi-experimental evaluation. Tools used included a quantitative survey questionnaire (n ¼ 183) and semi-structured interviews (n ¼ 32) with beneficiaries of peer education. Surveys were administered twice for beneficiaries of peer education (n ¼ 73), immediately after completion of the programme (post-test) and 4 months later (delayed post-test), and once for control group members (n ¼ 110). The three main methodological limitations in this study were the use of a once-off control group assessment as the baseline for comparison, without a pre-test, due to timing and resource constraints; a small sample size (n ¼ 183), which reduced the statistical power of the evaluation; and the unavailability of existing tested survey questions to measure the impact of peer education and its role in behaviour change. Findings: This article reports on the difficulties of designing a comprehensive evaluation within time and financial constraints, critically evaluates survey design with multi-item indicators, and discusses six statistically significant changes observed in Vhutshilo participants out of a 92-point survey. Youth struggling with poor quality education and living in economically fraught contexts with little social support, nonetheless, showed evidence of having greater knowledge of support networks and an expanded emotional repertoire by the end of the Vhutshilo programme, and 4 months later. At both individual and group level, many with low socio-economic status showed great improvement with regard to programme indicator scores. Conclusion: For the poorest adolescents, especially those living in the rural parts of South Africa, peer education has the potential to change future orientation, attitudes and knowledge regarding HIV and AIDS, including an intolerance for multiple concurrent partnerships. When well organised and properly supported, peer education programmes (and the Vhutshilo ...